1. Field of the Invention
This invention relates to improved connection between electrical cords. More particularly, it relates to an accessory for holding two electrical cords in connection and preventing their accidental disconnection.
2. Description of Background Art
There is a need for a simple, inexpensive, practical device to maintain the separable elements of an extension cord coupling against inadvertent separation. Frequently, the electrical cords of typical electrical equipment such as vacuum cleaners, hedge trimmers, industrial machinery such as hand drills, extension lights and the like, must be coupled to an extension cord to reach their desired location of use. The inherent strength of the coupling brought about by the friction between the prongs of one plug on the first cord and their corresponding receptacle on the second cord generally will not hold anything but the most moderate separating tension. This property is built into common household cords.
One solution to this has been the use of "twist-lock" connectors. These find acceptance in heavy-duty industrial and theatrical settings. "Twist-lock" connectors employ special prongs and receptors which are not compatible with normal home or light industrial wall plugs or with the connectors on normal extension cords. Accordingly, this solution, while effective in an industrial setting, does not work in many more common applications.
An alternative solution to the problem of cord separation has been to equip the connection with an appliance or accessory which holds the two ends of the connection in engagement. U.S. Pat. No. 3,383,639 to Anderson et al. shows a clamp device which fits around the two ends of a connection and holds the two connector halves in connection. Although this device has the advantage of being easy to use, it requires complete removal when the plugs are separated.
U.S. Pat. No. 3,014,194 to Berglund shows a cable connector protector which is a single body which clamps around the connected plug.
U.S. Pat. No. 3,030,601 to Krebs shows a very simple device which is a one-piece jacket formed of a rubberlike material which slips around the plugged-together cables.
U.S. Pat. No. 4,169,643 to Gallagher shows a mating clip wherein the connected ends of the receptacle and plug are latched within a closable container.
U.S. Pat. No. 4,643,505 to House, et al. shows a similar device in which a latched-together connector is clamped within a housing to secure its connection.
U.S. Pat. No. 4,690,476 to Morgenrath discloses an electrical connector securing system where each end of the coupling is equipped with a housing and the two housings are held together by straps.
U.S. Pat. No. 4,784,612 to Ryan discloses a pair of housings, one on each half of the connector, which thread together to secure the connector halves in a connected state.
All of these references suggest that there is a need for a good, efficient, inexpensive device for positively locking together electrical cords to prevent their uncoupling during use. Ideally, the device should be easy to engage and disengage while assuring the integrity of the connection when engaged. Also it is desirable if the locking device remains connected with the cord ends to prevent its accidental loss when not in use. Accordingly, it is an object of this invention to provide a simple and inexpensive device for securing together a pair of electrical plugs and to overcome the disadvantages associated with known devices of this type.